The present invention relates to an electric machine arrangement for an electric axle of a motor vehicle, having an electric machine which is connected via a gearbox to at least one drive shaft which can be connected to a driven wheel of the motor vehicle, and having a machine housing, wherein the electric machine has a stator fixed to the housing and a rotor which is connected to an input element of the gearbox.
In addition, the present invention relates to an electric axle for a motor vehicle, having two electric machine arrangements of the abovementioned type which are arranged in an essentially mirror-inverted fashion with respect to one another.
In the field of motor vehicle engineering, there is a trend towards electric drives. It is known in this context to combine an internal combustion engine with an electric machine. Such hybrid drive units can be configured in such a way that the electric machine only performs certain additional functions (referred to as a mild hybrid). It is also possible to construct a hybrid drive unit in such a way that both electric operation and operation with an internal combustion engine are possible.
In addition, purely electric drives are also known for motor vehicles, and the motor vehicle therefore has no internal combustion engine at all anymore.
In addition, what are referred to as electric axles are known in which one axle of the motor vehicle is driven in a purely electric fashion. Such electric axles can be installed in a motor vehicle as the sole drive axle. Alternatively it is possible to provide such an electric axle as a second driven axle, wherein a first driven axle is generally driven by a drive unit with a conventional internal combustion engine. In this case, a four-wheel drive can be implemented by means of the electric axle. Alternatively it is also possible to provide two electric axles in a motor vehicle for this purpose.
The electric axles can be constructed in such a way that an electric machine arrangement is combined with a mechanical differential. In addition, what are referred to as tandem drives are known in which the electric axle has two electric machine arrangements which are each assigned to one of the driven wheels of the axle. In this case, a mechanical differential is not necessary. The differential function is implemented by suitable actuation of the electric machines.
For large scale applications, the cost aspect is of particular importance here. In addition to the type and selection of the electric machine and of the gearbox, the type of design of the housing and of the bearing are important parameters here also.